Emerald Ash Borer

What to look for

Beginning in May the adult emerald ash borers emerge from under the bark and are present through August. Each adult leaves a D-shaped exit hole in the bark. They feed on ash leaves throughout the 3-6 week life span. Their feeding does not damage or affect the tree. Adults Emerald Ash Borers mate on the bark of trees after about a week of feeding and building strength. Eggs are laid on the surface of the bark, in bark cracks and crevices or just under the outer bark of ash trees. The eggs, which are very small and reddish-brown, may be laid in groups or individually. Eggs hatch in 2-3 weeks and the larvae immediately begin chewing through the outer bark to the phloem. Larvae begin feeding in late July, but most feeding and growth occur from August to October. Larvae feed in S-shaped tunnels, called galleries, in the phloem. As the larva feeds and grows, the galleries get larger. The galleries disrupt the transport of nutrients and water within, thus killing the tree.

How to prevent the spread

The Emerald Ash Borer is easily transported in hardwood and ash log firewood. State and Federal quarantine restrictions prohibit the movement of firewood due to the possible spread of the Emerald Ash Borer. Firewood should only be purchased locally from a known source. All firewood should be used during the cold months so that emerald ash borer larvae or adults do not survive on logs left through the spring.

Monitor your tree's health

The health of ash trees should be monitored by looking for dead and dying branches at the top of the tree’s crown. City Arborist, Gary Johnson, is the City of Galesburg’s local official authorized to conduct inspections of Ash trees within the City’s jurisdiction. Residents of Galesburg should contact Arborist Johnson for a site inspection if symptoms are seen on an Ash tree.